Trend of association of BoLA-DQA1 alleles with FMDV vaccine elicited immune response in crossbred cattle

Major histocompatibility complex molecules play a major role in immunological defense against pathogens. Polymorphism of bovine leukocyte antigen (BoLA) DQA1 gene is being intensively investigated for potential association with economically important diseases of cattle. Accordingly, we investigated the association of DQA1 Exon 2 polymorphism as evidenced by the variation in the binding pockets with variability in immune response to inactivated trivalent (O, A and Asia1) foot and mouth disease virus (FMDV) vaccine in a closed population of crossbred cattle. Antibody titer of >1.8 was set as the cutoff value to distinguish the protected (> 1.8) and unprotected (<1.8) animals. Eleven different alleles of over 1% frequency were detected in the population. Allele *0102 occupied highest rank followed by *10011 and *1402 for protective immune response while the allele *1401 ranked lowest for unprotected immune response for all the 3 serotypes. The correlation coefficient (ρ) of overall rank with individual ranks of serotype O, A, and Asia1 was also high in magnitude and positive. The rank correlations were statistically significant for all the serotypes except between O and Asia. Logistic regression analysis revealed that the effect of DQA1 alleles was nonsignificant on vaccine elicited immune response based on Wald statistics. However, it is evident that odds of protection is high [Exp (β)>1] for a good proportion of DQA1 alleles in a given serotype. The knowledge has potential implications in future selection programmes if integrated with the complete BoLA haplotype details and production traits of the herd.